Replace LED@Controller with LED-SMD

[Merlin04]

In the script generated, the part name for the SMD LED is "LED@Controller", which doesn't work. It should be LED-SMD.

[PaddleStroke]

I am having this issue too.
This remove the error but it put a package which is not WS2812B.
I checked the keyboard.lbr and found other packages that seem better suited for this : MX-1U-SMDRGB.

However the LED is soldered on bottom layer on this package. Which makes sens as it needs to be able to be assembled. But the WS2812B can be soldered upside down?